Biomass and volatile compounds of rose-scented geranium under various elicitors and cultivation systems

Abstract

The current experiment was conducted to investigate the biomass and essential oil of rose-scented geranium when exposed to elicitors. The plants were grown either in a soil medium or a soilless cultivation system. Elicitors, namely methyl jasmonate (MeJA)(150 and 300 μM) and salicylic acid (SA)(0.75 and 1.5 mM), were used as foliar applications. The measurements included evaluating physiological and biochemical parameters, as well as essential oil content and concentration. Additionally, aromatic compounds of geranium were assessed using the headspace and GC/MS method. Photosynthetic capacity and biomass were significantly higher in soilless-grown plants compared to soil-grown plants, particularly in terms of chlorophyll content, stomatal conductance, and leaf area. The biomass produced in the soilless system was ten times greater than that in soil-grown plants. MeJA and SA enhanced growth parameters and essential oil production. The interaction between the cultivation system and elicitors had a significant impact on biochemical and physiological traits. Notably, the highest photosynthetic capacity, biomass, essential oil concentration, and yield were achieved in plants treated with 300 μM MeJA and 0.75 mM SA concentrations under soilless media. The main constituents of volatile components in soilless-grown plants were linalool, citronellal, citronellol, and citronellyl formate. On the other hand, geranial and geranyl propionate were the predominant compounds in plants grown in soil. The citronellol:geraniol ratio (C/G ratio) served as a qualitative indicator of essential oil compounds in rose-scented geranium. The highest value of this ratio and the greatest essential oil yield were obtained in soilless-grown plants treated with 300 μM MeJA.